ABSTRACT
The observations on each variable have to be classified and presented in the form of tables. The main objectives of classification are to simplify the complex nature of the data, tailoring it up, and make it easy to grasp. In the classification of a qualitative variable data, a natural classification system may be available. In more complex situation of presentation, further to see the shape and pattern of frequency distribution, graphs and diagrams may be used with or without the frequency tables. They are good visual and mental aids for both professionals and laymen. Generally, the graphs are drawn for quantitative variable data and diagrams are drawn for qualitative variable data. In bar diagram, on a common base line, vertical or horizontal bars are drawn with their heights proportional to the frequencies. In histogram, on a common base line, rectangles are drawn with their areas proportional to the frequencies.
